[Prognostic significance of smoldering disease in multiple sclerosis, monitoring progression by imaging].

Disability progression can occur in all phenotypes of multiple sclerosis (MS) from the early stages of the disease, which may be due to incomplete recovery from clinical relapses and/or more insidious deterioration of neurological functions independent of relapses. Progression independent of relapse is more common in patients with progressive MS than in patients with relapsing-remitting MS. Its main background may be the activation of innate immune cells and the development of chronic active lesions, referred to as smoldering disease. Their identification may help in the early recognition of aggressive forms. Finding effective therapies targeting progressive mechanisms is a major need. A better understanding of the mechanisms underlying the progression of MS, the identification and validation of biomarkers and new therapeutic targets could lead to further success of therapies. In this communication, we summarize the theoretical background of smoldering disease and potential imaging modalities for its detection.